// Xunit.Sdk.ArgumentFormatter.FormatComplexValue
                // to see the real values of expectedStates, actualStates
                string FormatComplexValue(object value, Type type)
                {
                    var fields = type.GetRuntimeFields()
                        .Where(f => f.IsPublic && !f.IsStatic)
                        .Select(f => new { name = f.Name, value = f.GetValue(value) });
                    var properties = type.GetRuntimeProperties()
                        .Where(p => p.GetMethod != null && p.GetMethod.IsPublic)
                        .Select(p => new { name = p.Name, value = p.GetValue(value) });
                    var parameters = fields.Concat(properties)
                        .OrderBy(p => p.name)
                        .ToList();

                    if (parameters.Count == 0)
                    {
                        return $"{type.Name} {{ }}";
                    }

                    var formattedParameters = string.Join(", ", parameters
                        .Select(p => $"{p.name} = {p.value}"));

                    return $"{type.Name} {{ {formattedParameters} }}";
                }

                void LogEnumerable(string name, IEnumerable<object> enumerable)
                {
                    _output.WriteLine(
                        "{0} is {1}",
                        name,
                        string.Join(
                            ", ",
                            enumerable.Select((x, i) =>
                                (i % 3 == 0 ? "\n" : string.Empty) +
                                FormatComplexValue(x, x.GetType()))));
                }